1. Field of the Invention
The invention relates to a device for manufacturing laminated wood panels, and more particularly to a laminated wood panel manufacturing device having pressure strips of adjustable height allocated to each daylight stage.
2. Discussion of Related Art
Laminated wood panels consisting of a core layer and facing layers, also called bench panels, blockboard panels or plywood panels, are known in the art. German Offenlegungsschrift 3,517,449 discloses a method of manufacturing a laminated wood panel, wherein the laminated stacks, consisting of a core layer and facing layers applied to both sides, are put into the daylight stages of a multi-daylight press (also called a platen press), put down onto the heating plates and pressed. In this reference, the daylight stages are closed by lowering the upper heating plates until contact is made with the upper facing layers. Then the facing layers, which consist of wooden boards, are pressed together without gaps by means of pressure strips of a pressure device and, after the daylight stages are closed, pressed with the full pressing power and the heating energy provided.
According to this method, however, faulty pressings could be caused by the wooden boards wedging between pressure strips and heating plates when being pushed together without gaps. This disadvantage could occur in a feed system in which the individual laminated stacks are placed onto separate conveying plates and moved into the press. After the pressing, the conveying plates are conveyed out again and, in a plate-circulating system, are supplied again to the feed system for the press.
Another well-known method comprises a feed system which has no conveying plates and in which feeding and emptying is effected by endless conveying belts which are guided around the heating plates. In this system, the conveying belts can be made of steel or temperature-resistant plastic sheeting. Here, for feeding, pressing and emptying, the conveying belts must have a width which is greater than that of the laminated stacks to be processed. If narrower conveying belts were used, their lateral edges would leave a mark on the finished laminated wood panel. However, producing with projecting conveying belts again has the disadvantage that the pressure strips can seize and compress the conveying belts. In the process, folds can form or the conveying belts may even be destroyed.
In the press according to German Offenlegungsschrift 3,517,449, described above, distance strips of appropriate thickness are used for the particular thicknesses of laminated stacks to be pressed. This has the disadvantage that, for every new series of laminated stacks, the distance strips also have to be exchanged. Apart from the changeover time, this also calls for costly stock-keeping of the individual thicknesses of distance strips.